Drafting board



P. L. M. CHAIX DRAFTING BOARD 2 Sheets-Sheet l Filed June 28, 1938 ,l e I 5 l Il( 1. /hh avda?HkubnHunun355.5%- 3/ A\|\,f .f r/l l .ff/4l, J/ a l ,fww SE@ lL |.lllll H am m, e V

De 24, 1940- P. l.. M. cHAlx 2,225,903

DRAFTING BOARD Filed June 28, 1938 2 Sheets-Sheet 2 -ATro /vfr Patented Dec. 24. 1940 UNITED STATES PATENT OFFICE Application June 28, 1938, Serial No. 216,365

In France June 30, 1937 4 Claims.

The present invention relates to improvements in drafting boards. The main object of the invention is to provide a drafting board which provides for the drawing of various geometric figures 5 such as angles, circles, straight lines, perpendiculars, etc., without the aid of conventional drafting tools such as protractors, T-squares, triangles, rulers, and even compasses.

A further object of the invention ls to provide l a drafting board in which the paper or tracing cloth to be drawn upon can be conveniently mounted and adjusted relative to the supporting surface ofthe board.

Another object is to provide a .drafting board i whose supporting surface contains various Ageometric gures which may be traced upon the drawing, and wherein an arrangement is provided permitting relative adjustment between the supporting surface and the drawing sheet so that selected geometric figures on the supporting surface may be conveniently brought to position at the particular areas of the sheet where it is found necessary to draw the particular figures.

According to the invention the paper or tracing cloth is supported on a/pair of lateral cylinders which permit the same to be wound in both directions across the drafting board. Mounted beneath the drawing material between the cylinders is a slip-board providing a supporting surface for the drawing material, and which is adjustable so that different areas thereof may be brought into underlying relation with dierent areas of the drawing material. By adjustment of .the drawing sheet through its supporting cylinders, and adjustment of the slip-board relative to the sheet, different areas of the slip-board may be brought into juxtaposition with a` variety of points of the sheet.

The slip-board is provided with outlines of elementary geometric figures in different areas thereof, and through the arrangement just described these gures may-be brought into appropriate position relative to the sheet so that they may be transcribed onthe sheet without the necessity of drafting tools ordinarily used in drawing the same.

The invention is particularly useful for topographic drafting boards. In such case the slipboard will be inscribed with a mariners card, two opposite slope scales, la horizontal scale, an altitude scale, and various abacuses. It will be understood that any types of geometric figures may be used such as concentric circles, a series of angular graduations divided like a protractor, etc., 55 either with or without tables, and depending on (CIL 45-131) the particular type of work for which the drafting board is to be employed.

The invention for purposes of eld work may be conveniently provided with a strap arrangement which enables the device to be conveniently sup- 5 ported by the draftsmans body in working position while permitting ready adjustment of the drawing sheet and the slip-board.

In the drawings:

Fig. l is a plan view of a drafting board accord- 10 I ing to the invention;

Fig 2 is a cross-sectional elevation of the construction shown in Fig. 1; and

Fig. 3 shows a supporting strap arrangement for the drafting board and the manner in which the 15 same is held in relation to the draftsmans body.

The invention includes a wooden or non-magnetic metal frame I provided at opposite edges with parallel grooves 2 and 2' in which is slidably supported a -slip-board 3. A stop member 4 may be 20 provided at one end of the frame to limit movement of the slip-board in one direction so as not to come against the draftsmans body when the device is supported as shown in Figure 3.,

Projecting from the opposite sides of the frame 25 I at each end are supporting members such as 5,

5 and 6 providing bearings for rotatable shafts l and I to which are afxed cylinders Sand 9- upon which rolls the drawing material P which may be paper or tracing cloth. Knurled knobs 30 8 and 8 are supported at one or both ends of shafts 'I and 'I' throught which winding of the paper in either direction crosswise of the frame may be effected. In order that winding may be effected in either direction through the adjustment of 35 merely one knob, it is desirable to provide beneath the frame I an intermediate shaft I0 geared to the respective shafts through worm and helicoidal gears Il, I2 and Il', I2. Through this arrangement adjustment of either of the knobs 8, 8' will 40 cause simultaneous rotation of shafts I and 1 in the same direction, and adjustment of the drawing material in either direction F.

As previously stated, the slip-board 3 is adjustably mounted in frame I, and as shown it is 5 preferable that the same shall be movable in directions F at right angles to the directions F in which the winding of the drawing sheet occurs. Adjustment of the slip-board may be effected 50 through toothed racks II, I1' on the underside thereof which mesh with gears I6 and I6. The latter gears are supported on shaft I4 hung from bearings I5 at the-underside of the frame having knobs I3 and I3 for rotating the shaft. Rotation 55 of either of the knobs in either direction will adjust the slip-board I in the frame.

It will be evident that adjustment of the web through knobs I or l' and adjustment of the slipboard through knobs I3 or I3 will enable different points of the drawingsheet tobe brought into overlying relation with different points of the slipboard. If desired, vthe stop member 4 may be omitted which will materially increase the range of adjustment. In the present case the slip-board is inscribed with four groups of geometric figures. A represents a series of concentric: circles separated by a constant distance corresponding to the most usual scale for certain topographic work. It is possible to draw from the common center of all the circles a series of converging radii correspondl ing to graduations in grades, degrees, or thousandths, thus simulating a protractor. The radii may be divided and used as units of length measurement. B represents two slope scales of opposite inclination which may show slopes from up to 50 with graduations every two to ve points. C represents perpendicular coordinates, one series of lines adapted to produce a horizontal line and its parallels being divided into degrees, grades, or thousandths, the other series of lines being divided into spot angles: degrees, grades, thousandths, or slope in hundredths. At D is represented a table for the reduction to the horizontal of distances according to the equidistance slope of the level curves.

The four groups of figures described are particularly intended for topographic work, and it will be understood that additional or other types of geometric figures may be provided on the slipboard for other types of work. As shown in Figure l, hooks and eyelets I9 and 2| may be. provided at three corners of the frame l adapted to receive a series of supporting straps I8 and 20 arranged as in Figure 3. It will be observed that strap I8 passes from the upper and lower left hand corners of the device around the left shoulder of the draftsman, and that strap 20 connects with strap I8 at point I8' at the back of the left shoulder and passes downwardly around the right hand side of the body to connect with eyelet 2| at the lower right hand corner of the device. Thus the structure is securely supported in position for usage, leaving the hands free for adjustment of the various knobs and for actual drafting operations.

lt will be understood that the form of the invention shown is merely illustrative and that various changes may be made within the scope of the invention. Also, an entirely different form of supporting frame may be employed, providing carrying space for pencils, extra drawing material, etc.

What I claim is: g

l, A drafting board comprising a frame, a platen mounted for planar movement lengthwise in the frame, and means on the frame for movably supporting sheet drawing material over the platen for adjustment crosswise of the frame independently of and relative to the platen, and means for adjusting the platen lengthwise of the frame independently of and relative to the drawing material.

2. A drafting board comprising a frame, roller l means mounted on opposite sides of the frame for supporting sheet drawing material, a'platen mounted in the frame between the roller means to underlie and support the drawing material and. bearing geometric figures for tracing on the drawing material, means for adjusting the roller means to eifect planar movement of the drawing material crosswise relative to the platen, and means for adjusting the platen lengthwise in the frame relative to the roller means at right angles to the direction of movement of the drawing material, thereby to bring a selected area of the drawing material and a particular geometric figure into registry.

3. A drafting board comprising a frame, parallel shafts extending lengthwise of the frame and rotatably mounted at opposite sides thereof, an independently rotatable shaft extending crosswise ofI the frame, rollers fixed to the parallel shafts adapted to support a web of tracing sheet material foradjustment crosswise over the frame, a supporting board for the sheet material inscribed with geometric figures adapted to be traced thereon and mounted for lengthwise movement in the frame between the rollers, means for rotating the roller-carrying shafts to adjust the drawing material crosswise of the board so that any point on the drawing material can be brought to any position transversely of the board, and means actuated by said independently rotatable shaft for radjusting the board lengthwise in the frame independently of the drawing material so that any point on the drawing material can be brought to any position lengthwise of the board.

4:.A A drafting board comprising interconnected' spaced side frame members, rollers rotatably mounted lengthwise of the respective side frame members adapted to support a web of drawing material for crosswise adjustment over the space between the side frame members, and a supporting board for the drawing material tted between the side frame members inscribed with geometric figures such as are customarily executed with drafting tools adapted to be traced on the drawing material, said board being mounted for movement lengthwise of the side frame members independently of the rollers at right angles to the direction of movement of the drawing material whereby through correlative adjustment of the board lengthwise and adjustment of the web crosswise any area of the drafting material may be brought over a figure inscribed at any area of the board for tracing such ilgure on the drawing material.

PIERRE LOUIS MAURICE CHAIX. 

